Recognizing Eudesmia australis (Orfila, 1935)

Eudesmia australis (Orfila, 1935)

Cisthene australis Orfila, 1935. Rev. Soc. Entomol. Arg. 7:225-226.
Vianania australis Orfila, 1953. Physis 20(59):483-484.
[Bendib & Minet (1999) synonymized Vianania under Eudesmia.]

Resumen (español): Eudesmia australis se puede reconocer por las pequeñas manchas anaranjadas en el collar y las manchas anaranjadas subapicales "triangulares" en las alas anteriores. La especie se encuentra desde el estado de Santa Catarina, Brasil, hasta el sur del departamento de Buenos Aires, Argentina.


Eudesmia australis: Argentina @claudianr | Argentina @luchoperalta | Uruguay @gmmv80

Like other southern South American members of the genus, Eudesmia australis has (1) two orange subterminal patches instead of one orange crescent, and (2) a median orange or yellow band which often has irregular margins, bulges in the middle, and narrows at the costa and inner forewing margins. Of the two subterminal patches, the shape of the subapical one has been described as "subtriangular" or "triangular" (Orfila 1935, 1953), refering to the fact that the patch is widest in the middle, its basal edge forms a broad obtuse angle, and the distal margin is evenly and gently curved. This is similar to the same patch on E. ruficollis of Brazil and contrasts with the rectangular or crescentic subapical patch on E. argentinensis. The thorax is mostly black with two widely separated spots of orange on the collar, unlike the nearly continuous orange collar of both E. argentinensis and E. ruficollis. There appears to be a general trend for the orange on the collar to be slightly more extensive towards the northern part of the range of this species, thus approaching the continuous orange collar shown on E. ruficollis.

On iNaturalist, Eudesmia australis has been documented from southern Brazil, through Uruguay, and into southern Buenos Aires province, Argentina, where the species apparently overlaps with Eudesmia argentinensis. The westernmost images on iNaturalist are near Tornquist, Buenos Aires Province. The northernmost images are from the state of Santa Catarina, Brazil.


DRAFT map of the distribution of five species of Eudesmia in southern South America. Data are from iNaturalist observations as of 8 December 2022 plus a few earlier records from the literature.

Orfila, R. N. 1935. Lepidoptera Neotropica, II. Dos nuevas especies de Noctuoidea. Rev. Soc. Entomol. Arg. 7:225-226.

Orfila, R. N. 1953. Notas sobre Lithosiidae, I. El género Eudesmia Hb. y un género y especie nuevos. Physis 20:474-485.

Publicado por gcwarbler gcwarbler, 27 de noviembre de 2022

Comentarios

Thanks, Chuck! I'd not even heard of the genus Eudesmia before!
https://www.inaturalist.org/observations?place_id=any&taxon_id=247532

Publicado por sambiology hace 2 meses (Marca)

I've recently got intrigued by this genus. As a group they are quite recognizable, and there aren't too many species to overwhelm me (which happens with many other Arctiid genera). Once again, I've been digging through a bunch of old literature to sort these out and figure out how to recognize them. I soon noticed that several species were "missing" (unrecognized) among iNaturalist observations. Fun!

Publicado por gcwarbler hace 2 meses (Marca)

Tagging some additional folks who may be interested in this post: @lrubio7 @gafischer @enricotosto96 @amzamz

Publicado por gcwarbler hace 2 meses (Marca)

Great! It is something that intrigued me for some time, in the Museum of Mar del Plata there are specimens collected in Tandilia, identified as Eudesmia australis

Publicado por luchoperalta hace 2 meses (Marca)

Very interesting!! Thanks, Chuck!

Publicado por gafischer hace 2 meses (Marca)

@luchoperalta Perfecto! La localidad tipo (Orfila 1935) es en Tandil y las Sierras de Tandil.

Publicado por gcwarbler hace 2 meses (Marca)

Hi. I'm struggling to separate Eudesmia ruficollis from Eudesmia australis. Maybe the different terminology that are confusing me. I clearly see your point whit the collar difference but I was trying to use the key of Ricardo Orfila in the article that described Cisthene australis (now Eudesmia australis). Well, that key is not working, he separated this two species by the color of tegula: yellow for E. ruficollis and black for E. australis. I couldn't find none Eudesmia whit diference in tegula region. It's possible that the autor confused Patagia (collar) whit tegula? Because if he did, your and his way to separate this species are the same.

Publicado por regisrafael hace alrededor de 2 meses (Marca)

@regisrafael Tenho a chave de 1935 de Orfila à minha frente. Tenho que concordar que Orfila pode ter usado a terminologia errada (como eu a entendo) para algumas das faixas de escalas no/ao redor do tórax. Também concordo que ruficollis e argentinensis têm essencialmente o mesmo padrão de cor laranja no "colar", uma região que acredito ser composta pelas escamas da patagia, não da tegulae. Por outro lado, a maior parte do meio do colar no australis é preta e apenas as partes esquerda e direita das escamas são laranja. Entre as imagens no iNat, isso varia um pouco. Parece que os exemplos de australis no Departamento de Buenos Aires têm a menor quantidade de laranja nas bordas esquerda e direita do colar, enquanto os exemplos de australis no extremo sul do Brasil têm mais laranja, portanto a lacuna preta é mais estreita sobre estes. De qualquer forma, todos os ruficollis que vejo têm uma gola laranja sólida ou apenas uma linha preta mínima separando os lados direito e esquerdo da gola.

I have Orfila's 1935 key in front of me. I have to agree that Orfila may have used the wrong terminology (as I understand it) for some of the tracks of scales on/around the thorax. I also agree that ruficollis and argentinensis have essentially the same pattern of orange color on the "collar", a region which I believe is made up of the scales on the patagia, not the tegulae. By contrast, most of the middle of the collar on australis is black and only the far left and right patches of scales are orange. Among images on iNat, this varies somewhat however. It seems that examples of australis in Buenos Aires Dept. have the least amount of orange on the L and R edges of the collar, whereas examples of australis in southernmost Brazil have more orange, thus the black gap is narrower on these. In any event, all ruficollis I see have either a solid orange collar or only the slightest black line separating the right and left sides of the collar.

Publicado por gcwarbler hace alrededor de 2 meses (Marca)

UPDATE (12/20/22): Added a draft map of the distribution of the five southern South American species of Eudesmia/Vianania.

Publicado por gcwarbler hace alrededor de 1 mes (Marca)

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